Apparatus and methods for improving uniform cover tape adhesion on a carrier tape

ABSTRACT

Apparatus and methods are presented herein for uniformly sealing and peeling a cover tape to/from a carrier tape. The carrier tapes of the present invention include surface transitions that minimizes/eliminates surface irregularities and distortions such that the cover tapes can be uniformly sealed and peeled from the carrier tapes. The surface transitions act as physical barriers to prevent propagation of surface irregularities and distortions from the thermoformed pocket area into the heat bonding zones. The surface transitions also act as stiffening members to keep the heat bonding zones as flat as possible during subsequent handling of the carrier tape. The surface transitions may be in the form of continuous ribs and/or step portions.

FIELD OF THE INVENTION

The present invention relates to a carrier tape system used forpackaging, transporting, and automatically taking out components thatare placed in the pockets of a carrier tape. More particularly, thepresent invention is directed to apparatus and methods for uniformlysealing and peeling a cover tape that is used to protect the componentsplaced in the pockets of the carrier tape. Furthermore, the presentinvention provides apparatus and methods for minimizing or eliminatingsurface irregularities and distortions on bonding zones of the carriertape.

BACKGROUND OF THE INVENTION

Electronic components such as semiconductor chips, devices, integratedcircuits, and the like are generally developed and manufactured by onemanufacturer and transported to another manufacturer or customer forfurther processing. For example, after manufacturing semiconductor chipsin a fabrication or “clean room” facility, the chips are generallypackaged and transported to another manufacturer or customer, forexample, a computer wholesaler, so that the wholesaler can mount them toprinted circuit boards or the like.

When components are packaged and transported from one manufacturer toanother, it is critical that the components be packaged and transportedwith minimal damage. By their very nature, small electronic components(e.g., semiconductor chips, devices, and integrated circuits) are lightobjects and susceptible to damage. Thus, it is important that thesecomponents be packaged and transported in a manner thatminimizes/eliminates damage to them.

Currently, the semiconductor fabrication industry implements a JEDECstandard carrier tape system to package and transport semiconductorcomponents. Conventional carrier tape systems allow the componentmanufacturers to package and transport the components to their customerswith minimal damage while allowing the customers to efficiently unloadthe components using an automated pick and place machine.

FIGS. 1A-1C illustrate various views of a conventional carrier tapesystem. For example, FIG. 1A illustrates a perspective view, FIG. 1Billustrates a top view, and FIG. 1C illustrates a cutaway end view of asection taken along line A—A of the conventional carrier tape system.Reference will be made to FIGS. 1A-1C concurrently for a more completeunderstanding of the conventional system.

A conventional carrier tape 2 includes multiple thermoformed pockets 4formed along its longitudinal direction for storing individualcomponents 6. The carrier tape 2 also includes a row of advancementholes 8 formed longitudinally along one side of the carrier tape 2. Theadvancement holes 8 are used for locating and feeding the components 6into the automated pick and place machine (not shown).

In conventional carrier tape systems, surface irregularities anddistortions are typically formed on the top surface of the carrier tape2. These surface irregularities and distortions have a significantinfluence on the uniformity of the bonding strength between the carriertape 2 and the cover tape 10. Surface irregularities and distortions aregenerally formed on the carrier tape 2 as a result of thermoforming thepockets 4 or from subsequent handling of the carrier tape 2. Suchsurface irregularities and distortions may be in a form of small bumps14 or grooves 16, which propagate out from or between the pockets 4.

During the packaging process, the components 6 are loaded into thepockets 4 of the carrier tape 2. After the components 6 are successfullyloaded into the pockets 4, a cover tape 10 is applied over the pockets 4using, for example, a sealing iron (not shown) to secure the components6 contained therein. The cover tape 10 protects and retains thecomponents 6 in the pockets 4 of the carrier tape 2. In general, thecover tape 10 is heat bonded over the carrier tape 2 along a pair ofbonding portions 12. In other words, only the outer portions(corresponding to bonding portions 12) of the cover tape 10 are heatbonded to the carrier tape 2 along the longitudinal direction.

After sealing the pockets 4 of the carrier tape 2 with the cover tape10, the components 6 are transported to another manufacturer/customer.After receiving the carrier tape 2, it is fed into the pick and placemachine along its longitudinal direction using advancement holes 8. Thecover tape 10 is simultaneously peeled/removed from the carrier tape 2.Thereafter, the components 6 in the pockets 4 of the carrier tape 2 aretaken out and mounted to printed circuit boards or the like.

An important consideration using the heat bonding process as describedabove is that the cover tape 10 must be peeled back from the carriertape 2 with a uniform amount of force before the components 6 are takenout of the pockets 4. In other words, while separating the cover tape 10from the carrier tape 2, the force required for such separation shouldbe constant with respect to the longitudinal direction of the carriertape 2. However, because of surface irregularities and distortions, therequired separation force may not be constant. For example, a greaterforce may be required to separate the cover tape 10 from the carriertape 4 where there are “high spots” (i.e., bump 14 of FIG. 1C) and asmaller force may be required in regions where there are lower spots. Asa result, the force needed to separate/peel the cover tape 10 from thecarrier tape 2 may not be uniform from one region to another.Undulations may result in the carrier tape 2 as the cover tape 10 isseparated/peeled. Such undulations may undesirably separate thecomponents 6 from the pockets 4 of the carrier tape 2 or change theplacement of the components 6, thereby leading to obstructions in usingthe automated pick and place machine.

Small surface irregularities and distortions as described above cancause differences in contact pressure during the heat bonding process.As the cover tape 10 is sealed to the carrier tape 2 on the bondingportions 12, “high spots” will tend to bond better than lower spots,thereby causing variations in the bonding strength. Achieving uniformrelease tension is often very difficult when such variations in thebonding strength exists and continues to be a major problem in thecarrier tape industry.

FIG. 2A illustrates a top view and FIG. 2B illustrates an exploded topview of a section of another conventional carrier tape. Similar to thecarrier tape 2 of FIGS. 1A-1C, the carrier tape 22 includes multiplethermoformed pockets 24 for storing components and advancements holes 28for the automated pick and place machine. As shown in more detail,surface distortions 26 are formed on the carrier tape 22 fromthermoforming the pockets 24 and/or subsequent handling the carrier tape22. Such distortions 26 propagate to the heat bonding portions, therebyrequiring variations in the force needed to remove the cover tape fromthe carrier tape 22.

The carrier tape is made generally made from, but not limited to,thermoplastic resin, polystyrene or ABS (acrylonitrilebutadiene-styrene) with or without additives, and the cover tape is madefrom, but not limited to, polyester, polypropylene or polyethylenehaving heat sensitive adhesives with or without additives.

U.S. Pat. No. 4,736,841 ('841 patent) also discloses various examples ofother prior art carrier tape systems. One particular embodiment in the'841 patent includes a carrier tape that has a pair of step portionsextending longitudinally along opposite sides of the carrier tape. Theraised portions of the carrier tape are used as bonding portions to heatbond the cover tape thereto, where the step portions are also used asboundaries for applying the cover tape. Consequently, a recessed centerportion is prevented from making contact with the cover tape as the stepportions are used as physical boundaries. Thus, in this particular priorart embodiment, the boundaries of each of the bonding portions aredefined by the step portions, which extend longitudinally along thecarrier tape. In addition, the '841 patent does not address the problemof minimizing/eliminating surface irregularities and distortions in thebonding portions/zones of the carrier tape.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide apparatus andmethods for improving adhesion between a carrier tape and a cover tape.

It is another object of the present invention to provide apparatus andmethods for providing a more uniform sealing and peeling process betweena cover tape and a carrier tape.

It is a further object of the present invention to provide apparatus andmethods for minimizing/eliminating surface irregularities anddistortions from the bonding portions/zones of a carrier tape.

It is yet another object of the present invention to provide apparatusand methods for improving cover tape bond strength uniformity.

It is another object of the present invention to provide a carrier tapehaving surface transitions along each longitudinal side tominimize/eliminate surface irregularities and distortions on the bondingportions/zones of the carrier tape.

The present invention relates to apparatus and methods for sealing andpeeling a cover tape from a carrier tape in a uniform manner. Thecarrier tapes of the present invention include surface transitions thatminimizes/eliminates the presence of surface irregularities anddistortions on the carrier tape such that the cover tape can beuniformly applied and removed to/from the carrier tape. These surfacetransitions are used to improve bond strength uniformity between thecover tape and the carrier tape.

Apparatus and methods for minimizing/eliminating the presence of surfaceirregularities and distortions in bonding zones of the carrier tape isachieved by adding surface transitions along each longitudinal side ofthe carrier tape. This can be accomplished by adding a pair ofcontinuous ribs or step portions between the pockets and the heatbonding zones. In other embodiments, there can be more, than two surfacetransitions on the carrier tape (i.e., four continuous ribs, twocontinuous ribs on each side of the carrier tape extendinglongitudinally). The surface transitions act as physical barriers toprevent propagation of surface irregularities and distortions from thethermoformed pocket area to the heat bonding zones. In addition, thesurface transitions also act as stiffening members to help keep the heatbonding zones as flat as possible during subsequent handling of thecarrier tape.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the present invention willbecome apparent and more readily appreciated from the following detaileddescription of the presently preferred exemplary embodiments of theinvention taken in conjunction with the accompanying drawings, of which:

FIG. 1A illustrates a perspective view of a conventional carrier tapesystem;

FIG. 1B illustrates a top view of a conventional carrier tape system asshown in FIG. 1A;

FIG. 1C illustrates a cutaway end view of a conventional carrier systemas shown in FIG. 1A;

FIG. 2A illustrates a top view of another conventional carrier tape;

FIG. 2B illustrates an exploded top view of a section of theconventional carrier tape of FIG. 2A;

FIG. 3A illustrates a top perspective view of a carrier tape and covertape in accordance with the first preferred embodiment of the presentinvention;

FIG. 3B illustrates a bottom perspective view of a carrier tape inaccordance with the first preferred embodiment of the present invention;

FIG. 3C illustrates a side view of a carrier tape and cover tape inaccordance with the first preferred embodiment of the present invention;

FIG. 3D illustrates a cutaway top view of a carrier tape and cover tapein accordance with the first preferred embodiment of the presentinvention;

FIG. 3E illustrates a cutaway end view of a section of a carrier tapeand cover tape in accordance with the first preferred embodiment of thepresent invention;

FIG. 3F illustrates another top view of a carrier tape and cover tape inaccordance with the first preferred embodiment of the present invention;

FIG. 3G illustrates a cutaway end view of a cross section taken alongline I—I of FIG. 3F;

FIG. 3H illustrates a cutaway end view of a cross section taken alongline II—II of FIG. 3F;

FIG. 4A illustrates a top perspective view of a carrier tape and covertape in accordance with the second preferred embodiment of the presentinvention;

FIG. 4B illustrates a bottom perspective view of a carrier tape inaccordance with the second preferred embodiment of the presentinvention;

FIG. 4C illustrates a side view of a carrier tape and cover tape inaccordance with the second preferred embodiment of the presentinvention;

FIG. 4D illustrates a top view of a carrier tape and cover tape inaccordance with the second preferred embodiment of the presentinvention;

FIG. 4E illustrates a cutaway end view of a cross section taken alongline III—III of FIG. 4D; and

FIG. 4F illustrates a cutaway end view of a cross section taken alongline IV—IV of FIG. 4D.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in greater detail, which mayserve to further the understanding of the preferred embodiments of thepresent invention. As described elsewhere herein, various refinementsand substitutions of the various embodiments are possible based on theprinciples and teachings herein.

The preferred embodiments of the present invention will now be describedwith reference to FIGS. 3-4, wherein like components are designated bylike reference numerals throughout the various figures. Further,specific details and parameters are provided herein, and are intended tobe explanatory rather than limiting.

The present invention discloses apparatus and methods for minimizingand/or eliminating surface irregularities and distortions on a carriertape, particularly in the bonding portions/zones of the carrier tape.Surface transitions are formed longitudinally on the sides of thecarrier tape, thereby preventing surface irregularities and distortionsfrom being formed on the bonding portions/zones. In one embodiment ofthe present invention, surface transitions include a pair of continuousribs that are formed along the longitudinal sides of the carrier tape.In another embodiment of the present invention, a pair of step portionsare formed along the longitudinal sides of the carrier tape. In bothembodiments, surface irregularities and distortions areminimized/eliminated in the bonding zones of the carrier tape.

FIGS. 3A-3H illustrate a first preferred embodiment of the presentinvention. FIG. 3A illustrates a perspective top view, FIG. 3Billustrates a perspective bottom view, and FIG. 3C illustrates a sideview of a carrier tape 102 and cover tape 110 in accordance with thefirst preferred embodiment. The carrier tape 102 includes multiplethermoformed pockets 104 for storing and transporting the components106. Although each pocket 104 generally stores and transports one suchcomponent 106, in other embodiments, each pocket 104 can store andtransport two or more components 106. Along the longitudinal directionof the carrier tape 102, there are also formed advancement holes 108. Asdescribed in the background section, these advancement holes 108 areused by an automated pick and place machine in order to pick up thecomponents 106 from/into the pockets 104.

The carrier tape 102 further includes a pair of continuous ribs 120where each continuous rib extends longitudinally along two sides of thecarrier tape 102. When such ribs 120 are present, surface irregularitiesand distortions are minimized/eliminated in the bonding zones of thecarrier tape, as described in more detail later herein.

FIG. 3D illustrates a cutaway top view and FIG. 3E illustrates a cutawayend view of a section of a carrier tape 102 and cover tape 110 inaccordance with the first preferred embodiment of the present invention.The cover tape 110 is heat bonded to the carrier tape 102 along the heatbonding zones 130 (i.e., crossed-hatched area) using a conventional iron(not shown). Each of the two continuous ribs 120 is formed and extendslongitudinally in between the pockets 104 and the heat bonding zones130. The continuous ribs 120 may be formed having indents (spoon-likeconfiguration) facing upwards, as shown in FIGS. 3A-3H, or in thealternative, continuous ribs may be formed such that the indents arefacing downwards. In other words, the continuous ribs 120 as shown inFIGS. 3A-3H can be “flipped” 180 degrees such that the indents arefacing downwards, instead of upwards.

When surface irregularities and distortions are formed on the carriertape 102, the continuous ribs 120 acts as physical barriers bypreventing these surface irregularities and distortions from spreadingto the bonding zones 130. In this manner, the surface irregularities anddistortions are contained within the center portion of the carrier tape102. It is also noteworthy to note that the bonding zones 130 aretypically narrower than the contact area between the cover tape 110 andcarrier tape 102. Further, the surface transitions in this invention donot act as physical borders of the bonding zones, as distinguished fromthe embodiment described above relating to the '841 patent.

FIG. 3F illustrates another top view of a carrier tape 102 in accordancewith the first preferred embodiment of the present invention. FIG. 3F isillustrated herein to further show cutaway cross sectional views takenalong lines I—I and II—II for a more complete understanding of thepresent invention. For example, FIG. 3G and FIG. 3H illustrate cutawayend views of cross sections taken along lines I—I and lines II—II,respectively. Again, the continuous ribs 120 are formed in between thepockets 104 and the bonding zones 130.

In other embodiments, more than two continuous ribs (i.e., four, five,six, etc.) may be used as surface transitions on the carrier tape toprevent surface irregularities and distortions from forming on thebonding zones. For example, two pairs of continuous ribs, for a total offour continuous ribs, may be formed on the carrier tape. In this manner,one pair of continuous ribs may be formed longitudinally along one sideof the carrier tape, while another pair of continuous ribs may be formedon the other side of the carrier tape.

FIGS. 4A-4F illustrate a second preferred embodiment of the presentinvention. FIG. 4A illustrates a perspective top view, FIG. 4Billustrates a perspective bottom view, and FIG. 4C illustrates a sideview of a carrier tape 202 and cover tape 210 in accordance with thesecond preferred embodiment. Again, the carrier tape 202 includesadvancement holes 208 and multiple pockets 204 for storing andtransporting the components 106.

In the second embodiment of the invention, the carrier tape 202 includesa pair of step portions 220, as opposed to ribs 120, extendinglongitudinally along the two sides of the carrier tape. When such stepportions 220 are used, surface irregularities and distortions areminimized/eliminated in the bonding zones of the carrier tape in amanner similar to that described above.

FIG. 4D illustrates a top view of the carrier tape and cover tape inaccordance with the second preferred embodiment of the presentinvention. Referring to FIG. 4D, cutaway cross sectional views takenalong lines III—III and IV—IV are illustrated in FIGS. 4E and 4F,respectively, for a more complete understanding of the presentinvention.

Again, in other embodiments, more than two step portions may be used assurface transitions on the carrier tape to prevent surfaceirregularities and distortions from forming on the bonding zones,similar to that described above relating to continuous ribs.Furthermore, the present invention contemplates using both continuousribs and step portions on a single carrier tape to achieve the resultsdescribed above. For example, one continuous rib can be formedlongitudinally along one side of the carrier tape, and one step portioncan be formed longitudinally along the other side of the carrier tape.In this manner, both the continuous rib and step portion are used toprevent surface irregularities and distortions from forming on thebonding zones.

It is to be understood that in the foregoing discussion and appendedclaims, the term “components” include any electronic or non-electroniccomponents such as integrated circuits, memory chips, or semiconductordevices, etc.

In the previous descriptions, numerous specific details are set forth toprovide a thorough understanding of the present invention. However, asone having ordinary skill in the art would recognize, the presentinvention can be practiced without resorting to the details specificallyset forth.

Although various preferred embodiments have been described in detailabove, those skilled in the art will readily appreciate that manymodifications of the exemplary embodiments are possible withoutmaterially departing from the novel teachings and advantages of thisinvention.

I claim:
 1. An apparatus for storing a plurality of components,comprising: a carrier tape having; a plurality of pockets adapted toreceive the plurality of components, the plurality of pockets beingformed along a longitudinal direction of the carrier tape; a pair ofbonding zones, each bonding zone formed longitudinally along the outerperiphery of the carrier tape on opposite sides of the plurality ofpockets; a pair of step portions formed along the longitudinal directionof the carrier tape, wherein each of the step portions is formed inbetween the plurality of pockets and one of the pair of bonding zones,and wherein the pair of the step portions assist in providing asubstantially uniform surface having minimal surface distortions on thepair of bonding zones, wherein the step portions are spaced apart fromthe bonding zones; and a cover tape adapted to cover the plurality ofpockets and bonded to the carrier tape at the pair of bonding zones suchthat the plurality of components are retained therein.
 2. The apparatusaccording to claim 1, wherein the carrier tape further comprises aplurality of advancement holes formed longitudinally adjacent to one ofthe pair of bonding zones.
 3. The apparatus according to claim 1,wherein the carrier tape is made from one of thermoplastic resin,polystyrene, and ABS.
 4. The apparatus according to claim 1, wherein thecover tape is made from one of polyester, polypropylene, andpolyethylene.
 5. The apparatus according to claim 1, wherein the carriertape further includes a second pair of step portions, each of the secondpair of step portions extending longitudinally adjacent to one of theoriginal pair of step portions.
 6. The apparatus according to claim 1,wherein the cover tape is heat bonded to the carrier tape at the pair ofbonding zones.
 7. The apparatus according to claim 1, wherein the covertape is bonded to the pair of bonding zones with a substantially uniformtape release tension along the longitudinal direction of the carriertape.
 8. A method of manufacturing a carrier tape, the method comprisingthe steps of: identifying a pocket forming zone and a pair of bondingzones, each of the pair of bonding zones being disposed in alongitudinal direction of the carrier tape on opposite sides of thepocket forming zone; and forming a plurality of pockets in the carriertape within the pocket forming zone and a pair of surface transitions inthe carrier tape such that the presence of surface distortions on thebonding zones is minimal, each of the pair of surface transitionsdisposed in the longitudinal direction of the carrier tape in betweenthe pocket forming zone and one of the bonding zones, wherein thesurface transitions are spaced apart from the bonding zones.
 9. Themethod according to claim 8, wherein the step of forming the pluralityof pockets includes the step of thermoforming the pockets.
 10. Themethod according to claim 8, wherein each of the pair of surfacetransitions comprises a step portion.
 11. A system for packaging aplurality of components in a plurality of pockets of a carrier tape,comprising; means for positioning the plurality of components in theplurality of pockets; means for sealing the plurality of pockets using acover tape, wherein the cover tape seals the plurality of pockets onbonding zones of the carrier tape, and means for minimizing the presenceof surface distortions on the bonding zones, wherein the means forminimizing comprises forming at least one surface transition in betweenthe plurality of the pockets and the associated bonding zone on thecarrier tape before positioning the plurality of components in theplurality of pockets, and wherein the at least one surface transitionassists in providing a substantially uniform surface on the bondingzones, wherein the at least one surface transition is spaced apart fromthe associated bonding zone.
 12. The system according to claim 11,wherein the means for sealing the plurality of pockets includespositioning the cover tape on the bonding zones in a longitudinaldirection of the carrier tape.
 13. The system according to claim 11,wherein the at least one surface transition comprise a step portion. 14.The system according to claim 11, wherein the carrier tape furthercomprises a plurality of advancement holes formed longitudinallyadjacent to one of the bonding zones.
 15. The system according to claim11, wherein the plurality of components comprises one of semiconductorchips, devices, and integrated circuits.
 16. The system according toclaim 11, wherein the carrier tape is made from one of thermoplasticresin, polystyrene, and ABS.
 17. The system according to claim 11,wherein the cover tape is made from one of polyester, polypropylene, andpolyethylene.
 18. The system according to claim 11, wherein the meansfor sealing comprises heat bonding the cover tape to the carrier tape atthe bonding zones.